81177072 has 20 divisors (see below), whose sum is σ = 209707560. Its totient is φ = 27059008.

The previous prime is 81177059. The next prime is 81177073. The reversal of 81177072 is 27077118.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81177073) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 845547 + ... + 845642.

It is an arithmetic number, because the mean of its divisors is an integer number (10485378).

Almost surely, 2^81177072 is an apocalyptic number.

It is an amenable number.

81177072 is an abundant number, since it is smaller than the sum of its proper divisors (128530488).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

81177072 is a wasteful number, since it uses less digits than its factorization.

81177072 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1691200 (or 1691194 counting only the distinct ones).

The product of its (nonzero) digits is 5488, while the sum is 33.

The square root of 81177072 is about 9009.8319629170. The cubic root of 81177072 is about 432.9899280637.

The spelling of 81177072 in words is "eighty-one million, one hundred seventy-seven thousand, seventy-two".